Question

Write a chemical equation for the reaction of aqueous solutions of sodium carbonate and calcium sulfate to give calcium carbonate precipitate and aqueous sodium sulfate. Express your answer as a chemical equation. Identify all of the phases in your answer.

Answer 1

Answer:

Na₂CO₃(aq) + CaSO₄(aq) ⟶ CaCO₃(s) + Na₂SO₄(aq)

Explanation:

We can use the criss-cross method to work out the formulas of the compounds.  

The steps are

1. Write the symbols of the anion and cation.
2. Criss-cross the numbers of the charges to become the subscripts of the other ion.
3. Write the formula with the new subscripts.
4. Divide the subscripts by their highest common factor.
5. Omit all subscripts that are 1.

When we use this method, the formula for the compound formed from Na⁺ and CO₃²⁻ becomes Na₂CO₃ .

The table below lists the formulas for the possible combinations.

$\begin{array}{lcc}& \textbf{CO}_{3}^{2-} & \textbf{SO}_{4}^{2-}\\\textbf{Na}^{+} & \text{Na _{2} CO _{3} } & \text{Na _{2} SO}_{4}\\\textbf{Ca}^{2+} & \text{CaCO}_{3} & \text{CaSO _{4} }\\\end{array}$